How to send a Slack notification when there's a recording to watch

posthog.init('<ph_project_api_key>', {
    api_host: 'https://us.i.posthog.com',
    loaded: (ph) => {
      let checkInterval

      // this will be called every time a new sesson starts
      ph.onSessionId((sessionId) => {
        clearInterval(checkInterval)

        // setup a check for the condition that means the recording is interesting enough to be watched
        checkInterval = setInterval(() => {
          // we want to read the session data, but not change it, so we pass `true`
          const { 
            lastActivityTimestamp, 
            // or maybe sessionStartTimestamp, 
            sessionId 
           } = ph.sessionManager.checkAndGetSessionAndWindowId(true)
            
            const sinceLastActivity = Math.abs(new Date().getTime() - lastActivityTimestamp)
            const fiveMinutesInMillis = 5 * 60 * 1000
            if (sinceLastActivity > fiveMinutesInMillis) {
                // capture an event that will be used to trigger the posthog destination
              ph.capture('session_idle_for_five_minutes', {
                sessionURL: ph.get_session_replay_url({ withTimestamp: true }),
                idleSessionId: sessionId,
              })

              // clear the interval so we only send the event once
              clearInterval(checkInterval)
            }
          
        }, 5000)
      })
    }
  })

[
  {
    "text": {
      "text": "*{person.name}* has a recording available to watch",
      "type": "mrkdwn"
    },
    "type": "section"
  },
  {
    "type": "actions",
    "elements": [
      {
        "url": "{person.url}",
        "text": {
          "text": "View Person in PostHog",
          "type": "plain_text"
        },
        "type": "button"
      },
      {
        "url": "{event.properties.sessionURL}",
        "text": {
          "text": "Replay URL",
          "type": "plain_text"
        },
        "type": "button"
      }
    ]
  }
]